Prince Charles turned 70 years old on Wednesday, and there’s no better way to celebrate than talking about something peculiar Prince Charles does. In an interview with U.K. magazine Country Life,Prince William revealed that his dad, who guest-edited this month’s issue, has the strange habit of allowing red squirrels to come into his home at this Birkhall estate in Scotland.

“He is completely infatuated by the red squirrels that live around the [Birkhall] estate in Scotland—to the extent that he’s given them names and is allowing them into the house!” People uncovered Charles himself talking about his affection for the creatures in the Country Life issue.

“They come into the house at Birkhall, and we get them chasing each other round and round inside,” he said. “If I sit there quietly, they will do so around me. Sometimes, when I leave my jackets on a chair with nuts in the pockets, I see them with their tails sticking out, as they hunt for nuts—they are incredibly special creatures.”

The future king of Britain, who also enjoys painting watercolors, has apparently encouraged his sons to embrace nature (though maybe not as much as he does).

“His passion for the environment and the natural world is something I want to repeat in the way I raise George,Charlotte, and Louis,” William added.

John Bridcut, the filmmaker of Prince, Son and Heir: Charles at 70, the new documentary about Charles, told Vanity Fair that the prince rejects selfies and most modern technology. He did not say anything, however, about being against gun salutes; he, his mother, and his father receive the 41-gun salute on their birthdays. The basic salute is 21, but when the shots are fired from a royal park, as they were for Charles from Green Park on Wednesday, the birthday person gets an extra 20.